What does a Mayo 1 score for colonoscopy (colo) findings indicate in ulcerative colitis patients?

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Mayo 1 Score for Colonoscopy Findings in Ulcerative Colitis

A Mayo endoscopic subscore of 1 in ulcerative colitis indicates mild disease characterized by erythema, decreased vascular pattern, and mild friability of the colonic mucosa. 1

Understanding the Mayo Endoscopic Subscore

The Mayo endoscopic subscore is part of the full Mayo Clinic Score, which is widely used to assess disease activity in ulcerative colitis. The endoscopic component specifically evaluates the appearance of the colonic mucosa during colonoscopy.

The Mayo endoscopic subscore ranges from 0-3:

  • Mayo 0: Normal or inactive disease (completely normal mucosa) 1
  • Mayo 1: Mild disease (erythema, decreased vascular pattern, mild friability) 1
  • Mayo 2: Moderate disease (marked erythema, absence of vascular pattern, friability, erosions) 1
  • Mayo 3: Severe disease (spontaneous bleeding, ulcerations) 1

Clinical Significance of Mayo 1 Score

A Mayo endoscopic subscore of 1 has important implications for patient management and prognosis:

  • While often considered part of "mucosal healing" in clinical trials alongside Mayo 0, patients with Mayo 1 have significantly higher risk of relapse than those with Mayo 0 2
  • Patients with Mayo 1 have a 36.6% relapse rate within 6 months compared to only 9.4% for patients with Mayo 0 2
  • The presence of histologic activity in patients with Mayo 1 further increases relapse risk 3

Treatment Implications

The higher relapse risk associated with Mayo 1 has important treatment implications:

  • Therapeutic intervention for patients with Mayo 1 may prevent disease relapse 4
  • Patients with Mayo 1 and histologic activity plus previous steroid use history have a 39.4% two-year relapse rate 3
  • The concept of mucosal healing should ideally be limited to patients with an endoscopic Mayo score of 0 2

Relationship to Other Scoring Systems

The Mayo endoscopic subscore is one of several scoring systems used in ulcerative colitis:

  • The Ulcerative Colitis Endoscopic Index of Severity (UCEIS) is another validated scoring system that evaluates vascular pattern, bleeding, and erosions/ulcers 1
  • The Mayo score is simpler and more widely used in clinical practice, while UCEIS may offer better interobserver agreement 1
  • The partial Mayo score (excluding endoscopy) correlates well with the full Mayo score for assessing clinical response 5

Practical Application

When evaluating a colonoscopy report with Mayo 1 score:

  • Recognize this represents mild but active disease 1
  • Consider additional therapeutic intervention to prevent relapse 4
  • Assess for histologic activity which may further stratify relapse risk 3
  • Monitor more closely than patients with Mayo 0 due to higher relapse risk 2

Pitfalls and Caveats

  • Despite being classified as "mucosal healing" in many clinical trials, Mayo 1 carries significantly higher relapse risk than Mayo 0 2
  • Interobserver agreement for Mayo endoscopic scoring can vary from fair to high 1
  • The Mayo score lacks formal validation compared to newer indices like UCEIS 1
  • Histologic inflammation may persist despite endoscopic improvement to Mayo 1 3

References

1
Guideline

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Dr.Oracle Medical Advisory Board & Editors, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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